CSC 221: Introduction to Programming. Fall 2013

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1 CSC 221: Introduction to Programming Fall 2013 Computer basics and history hardware vs. software generations of computer technology evolution of programming why Python? 1 hardware vs. software basic terminology: hardware the physical components of the computer e.g., processor (Intel Core i5, AMD A6, Intel Pentium Mobile) memory (RAM, cache, hard drive, floppy drive, flash stick) input/output devices (keyboard, mouse, monitor, speaker) software programs that run on the hardware e.g., operating system (Windows 8, Mac OS X, Linux) applications (Word, Excel, PowerPoint, RealPlayer, IE, Firefox) development tools (JDK, BlueJ,.NET, IDLE, Scratch) The easiest way to tell the difference between hardware and software is to kick it. If it hurts your toe, it s hardware. Carl Farrell 2 1

History of computing technology DYK? When were "modern" computers invented? When were computers accessible/affordable to individuals? When was the Internet born? When was the Web invented?

transistors 3. integrated circuits 4. very large scale integration 5.

followed 1805 the first programmable device was Jacquard's loom the loom wove tapestries with elaborate, programmable patterns a pattern was represented by metal punch-cards, fed into the loom using

2 History of computing technology DYK? When were "modern" computers invented? When were computers accessible/affordable to individuals? When was the Internet born? When was the Web invented? How did Bill Gates get so rich? the history of computers can be divided into generations, with each generation defined by a technological breakthrough 0. gears and relays 1. vacuum tubes 2. transistors 3. integrated circuits 4. very large scale integration 5. parallel processing & networking 3 Generation 0: Mechanical Computers 1642 Pascal built a mechanical calculating machine used mechanical gears, a hand-crank, dials and knobs other similar machines followed 1805 the first programmable device was Jacquard's loom the loom wove tapestries with elaborate, programmable patterns a pattern was represented by metal punch-cards, fed into the loom using the loom, it became possible to mass-produce tapestries, and even reprogram it to produce different patterns simply by changing the cards mid 1800's Babbage designed his "analytical engine" its design expanded upon mechanical calculators, but was programmable via punchcards (similar to Jacquard's loom) Babbage's vision described the general layout of modern computers he never completed a functional machine his design was beyond the technology of the day 4 2

extensively in early telephone exchanges Zuse (Nazi Germany) his machines were destroyed in WWII Atanasoff (Iowa State) built a partially-working machine with his grad student Stibitz (Bell Labs)

faster than previous technology 5 Generation 1: Vacuum Tubes mid 1940's vacuum tubes replaced relays a vacuum tube is a light bulb containing a partial vacuum to speed electron flow vacuum tubes

3 Generation 0 (cont.) 1930's several engineers independently built "computers" using electromagnetic relays an electromagnetic relay is physical switch, which can be opened/closed via electrical current relays were used extensively in early telephone exchanges Zuse (Nazi Germany) his machines were destroyed in WWII Atanasoff (Iowa State) built a partially-working machine with his grad student Stibitz (Bell Labs) built the MARK I computer that followed the designs of Babbage limited capabilities by modern standards: could store only 72 numbers, required 1/10 sec to add, 6 sec to multiply still, 100 times faster than previous technology 5 Generation 1: Vacuum Tubes mid 1940's vacuum tubes replaced relays a vacuum tube is a light bulb containing a partial vacuum to speed electron flow vacuum tubes could control the flow of electricity faster than relays since they had no moving parts invented by Lee de Forest in 's hybrid computers using vacuum tubes and relays were built COLOSSUS (1943) first "electronic computer", built by the British govt. (based on designs by Alan Turing) used to decode Nazi communications during the war the computer was top-secret, so did not influence other researchers ENIAC (1946) first publicly-acknowledged "electronic computer", built by Eckert & Mauchly (UPenn) contained 18,000 vacuum tubes and 1,500 relays weighed 30 tons, consumed 140 kwatts 6 3

idea of a "stored program" computer Memory stores both data and programs Central Processing Unit (CPU) executes by loading program instructions from memory and executing them in sequence Input/Output

4 Generation 1 (cont.) COLOSSUS and ENIAC were not general purpose computers could enter input using dials & knobs, paper tape but to perform a different computation, needed to reconfigure von Neumann popularized the idea of a "stored program" computer Memory stores both data and programs Central Processing Unit (CPU) executes by loading program instructions from memory and executing them in sequence Input/Output devices allow for interaction with the user virtually all modern machines follow this von Neumann Architecture (note: same basic design as Babbage) programming was still difficult and tedious each machine had its own machine language, 0's & 1's corresponding to the settings of physical components in 1950's, assembly languages replaced 0's & 1's with mnemonic names e.g., ADD instead of Generation 2: Transistors mid 1950's transistors began to replace tubes a transistor is a piece of silicon whose conductivity can be turned on and off using an electric current they performed the same switching function of vacuum tubes, but were smaller, faster, more reliable, and cheaper to mass produce invented by Bardeen, Brattain, & Shockley in 1948 (earning them the 1956 Nobel Prize in physics) some historians claim the transistor was the most important invention of the 20th century computers became commercial as cost dropped high-level languages were designed to make programming more natural FORTRAN (1957, Backus at IBM) LISP (1959, McCarthy at MIT) BASIC (1959, Kemeny at Dartmouth) COBOL (1960, Murray-Hopper at DOD) the computer industry grew as businesses could afford to buy and use computers Eckert-Mauchly (1951), DEC (1957) IBM became market force in 1960's 8 4

Generation 3: Integrated Circuits mid 1960's - integrated circuits (IC) were produced Noyce and Kilby independently developed techniques for packaging transistors and circuitry on a silicon chip

microprocessor, the 4004, a chip with all the circuitry for a calculator 1960's saw the rise of Operating Systems recall: an operating system is a collection of programs that manage peripheral

specialized programming languages were developed Pascal (1971, Wirth), C (1972, Ritchie) 9 Generation 4: VLSI late 1970's - Very Large Scale Integration (VLSI) by the late 1970's, manufacturing

5 Generation 3: Integrated Circuits mid 1960's - integrated circuits (IC) were produced Noyce and Kilby independently developed techniques for packaging transistors and circuitry on a silicon chip (Kilby won the 2000 Nobel Prize in physics) this advance was made possible by miniaturization & improved manufacturing allowed for mass-producing useful circuitry 1971 Intel marketed the first microprocessor, the 4004, a chip with all the circuitry for a calculator 1960's saw the rise of Operating Systems recall: an operating system is a collection of programs that manage peripheral devices and other resources in the 60's, operating systems enabled time-sharing, where users share a computer by swapping jobs in and out as computers became affordable to small businesses, specialized programming languages were developed Pascal (1971, Wirth), C (1972, Ritchie) 9 Generation 4: VLSI late 1970's - Very Large Scale Integration (VLSI) by the late 1970's, manufacturing advances allowed forhundreds of thousands of transistors w/ circuitry on a chip this "very large scale integration" resulted in mass-produced microprocessors and other useful IC's since computers could be constructed by simply connecting powerful IC's and peripheral devices, they were easier to make and more affordable from Wikipedia 10 5

Apple went from Jobs' garage to $120 million in sales by 1980 1980 - IBM introduced PC Microsoft licensed the DOS operating system to IBM 1984 - Apple countered with Macintosh introduced the modern

program as a collection of interacting software objects that model real-world entities Smalltalk (Kay, 1980), C++ (Stroustrup, 1985), Java (Sun, 1995) 11 Generation 5: Parallelism/Networks the latest

6 Generation 4: VLSI (cont.) with VLSI came the rise of personal computing Bill Gates & Paul Allen founded Microsoft Gates wrote a BASIC interpreter for the first PC (Altair) Steve Wozniak & Steve Jobs founded Apple went from Jobs' garage to $120 million in sales by IBM introduced PC Microsoft licensed the DOS operating system to IBM Apple countered with Macintosh introduced the modern GUI-based OS (which was mostly developed at Xerox) Microsoft countered with Windows 1980's - object-oriented programming began represented a new approach to program design which views a program as a collection of interacting software objects that model real-world entities Smalltalk (Kay, 1980), C++ (Stroustrup, 1985), Java (Sun, 1995) 11 Generation 5: Parallelism/Networks the latest generation of computers is still hotly debated no new switching technologies, but changes in usage have occurred parallel processing has become widespread multi-core processors provide simple parallelism, can spread jobs across cores similarly, high-end machines (e.g. Web servers) can have multiple CPU's in 1997, highly parallel Deep Blue beat Kasparov in a chess match most computers today are networked the Internet traces its roots to the 1969 ARPANet mainly used by government & universities until the late 80s/early 90s the Web was invented by Tim Berners-Lee in 1989, to allow physics researchers to share data 1993: Marc Andreessen & Eric Bina developed Mosaic 1994: Andreesen & Netscape released Navigator 1995: Microsoft released Internet Explorer in 2009, 55% of American adults connected to Internet wirelessly, >30% using a smart phone (Internet Software Consortium & Netcraft, April 2010.) 12 6

Computers or devices? CISCO Internet Solutions Business Group claims that the "Internet of Things" was born around 2008 13 Computing entrepreneurs Richest People in the World (Forbes, 3/13) 1.

7 Computers or devices? CISCO Internet Solutions Business Group claims that the "Internet of Things" was born around Computing entrepreneurs Richest People in the World (Forbes, 3/13) 1. Carlos Slim Helu $73.0 billion Age: Bill Gates $67.0 billion Age: Amancio Ortega $57.0 billion Age: Warren Buffet $53.5 billion Age: Larry Ellison $43.0 billion Age: Jeff Bezos $25.2 billion Age: Larry Page $23.0 billion Age: Sergei Brin $22.8 billion Age: Michael Dell $15.3 billion Age: Steve Ballmer $15.7 billion Age: Paul Allen $15.0 billion Age: Mark Zuckerberg $13.3 billion Age: Azim Premji $11.2 billion Age: Laurene Jobs $10.7 billion Age:

8 Evolution of programming: machine language late 40 s / early 50 s: programmers coded directly in machine language each machine had its own set of instructions (sequences of 0's & 1's) corresponding to its underlying hardware extremely tedious, error-prone Evolution of programming: assembly language mid 1950 s: assembly languages replaced numeric codes with mnemonic names an assembler is a program that translates assembly code into machine code input: assembly language program output: machine language program still low-level & machine-specific, but easier to program gcc2_compiled.:.global _Q_qtod.section ".rodata".align 8.LLC0:.asciz "Hello world!".section ".text".align 4.global main.type main,#function.proc 04 main:!#prologue# 0 save %sp,-112,%sp!#prologue# 1 sethi %hi(cout),%o1 or %o1,%lo(cout),%o0 sethi %hi(.llc0),%o2 or %o2,%lo(.llc0),%o1 call ls 7ostreamPCc,0 nop mov %o0,%l0 mov %l0,%o0 sethi %hi(endl FR7ostream),%o2 or %o2,%lo(endl FR7ostream),%o1 call ls 7ostreamPFR7ostream_R7ostream,0 nop mov 0,%i0 b.ll230 nop.ll230: ret restore.llfe1:.size main,.llfe1-main.ident "GCC: (GNU) 2.7.2" 16 8

9 Evolution of programming: high-level language late 1950's present: high-level languages allow the programmer to think at a higher-level of abstraction a compiler is a program that translates high-level code into machine code /* Hello World in C */ #include<stdio.h> main() { printf("hello World"); } print("hello World!") input: C language program output: machine language program similar to assembler, but more complex an interpreter is a program that reads and executes each language statement in sequence Python programs are first compiled into a virtual machine language (bytecode) then the bytecode is executed by an interpreter (Python Virtual Machine) 17 Why Python? Python is a simple, but industry-strength, scripting language very simple language, designed for getting things to work with minimal overhead can be used for rapid development, but also supports object-oriented programming scripting languages (e.g., Python, PHP, perl, JavaScript) are growing in popularity note: we will be using Python 3 (not 2) 18 9

10 If you want to know more check out the following (purely optional) links Inventors: The History of Computers Computer Museum History Center Transistorized! from PBS.org Apple Computer Reading List The History of Microsoft Internet Pioneers: Tim Berners-Lee Internet Pioneers: Marc Andreessen Wikipedia entry on Programming Languages Webopedia entry on Programming Languages Python Official Website 19 10

CSC 221: Introduction to Programming. Fall 2011

CSC 221: Introduction to Programming Fall 2011 Computer basics and history hardware vs. software generations of computer technology evolution of programming why Python? 1 hardware vs. software basic terminology: